An “assay run” is an investigative (analytic) event, e.g., in laboratory medicine, pharmacology, analytical chemistry, environmental biology, or molecular biology, for qualitatively assessing or quantitatively measuring the presence, amount, or the functional activity of a sample, which can be a drug, biochemical substance, or a cell in an organism or an organic sample. The assay run usually aims to measure an intensive property of the sample and express it in the relevant measurement unit (e.g. molarity, density, functional activity in enzyme international units, degree of some effect in comparison to a standard, etc.) An assay can involve reacting a sample with certain reagents. An assay run is typically an instance of an assay procedure conforming to a (possibly standardized) assay protocol. An assay protocol commonly involves a set of reagent and/or sample fluids being dispensed in specific amounts to assay reaction sites, as well, sometimes, as additional steps such as mixing, separation, heating or cooling, incubation, and eventually one or more read-outs. The reproducibility and run-to-run comparability of an assay depends on the reproduction of its protocol.
Automated assay fluid dispensing systems can dispense assay fluids, e.g., samples and reagents, in a precise, controlled fashion to multiple reaction sites in a short time; for example, a carefully formulated mixture of several reagents, including a target species of interest, can be carefully formulated at multiple reaction sites for the testing of a set of test sample reagents at multiple concentrations. This allows many reactions to proceed contemporaneously. The automation reduces user effort and user-caused variability, while the concurrency further reduces the time to complete a complex assay.